Abstract

This paper investigates the impact of lameness on milk yield. The dataset used included approximately 8,000 test day milk yields from 900 cows collected over IS months from 1997 to 1999. The data were analysed to account for this auto-correlation. Farm of origin, stage of lactation, parity and whether a cow ever became lame influenced milk yield. In clinically lame cows, milk yield was reduced for up to four months before a case of lameness was diagnosed and treated and, for the five months after treatment. The total mean estimated reduction in milk yield per 305 day lactation was approximately 360kg. It was concluded that clinical lameness has a significant impact on milk production. This is important information for assessing the economic impact of clinical lameness and its impact on cow health. This finding adds weight to the importance of early identification of clinical lameness and the urgency required for techniques to improve the definition of this highly subjective diagnosis.